Novel methods for cleaning ion implanter components

ABSTRACT

A method and apparatus for cleaning residue from components of an ion source region of an ion implanter used in the fabrication of microelectronic devices. To effectively remove residue, the components are contacted with a gas-phase reactive halide composition for sufficient time and under sufficient conditions to at least partially remove the residue. The gas-phase reactive halide composition is chosen to react selectively with the residue, while not reacting with the components of the ion source region or the vacuum chamber.

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for cleaning thevacuum chamber and beamline of an ion implantation system used in thefabrication of a microelectronic device. In addition, the presentinvention relates to a method for the in situ cleaning of cryogenicpumps to remove purge resistant effluent material.

DESCRIPTION OF THE RELATED ART

Ion implantation is used in integrated circuit fabrication to accuratelyintroduce controlled amounts of dopant impurities into semiconductorwafers and is a crucial process in microelectronic/semiconductormanufacturing. In such implantation systems, an ion source ionizes adesired dopant element gas and the ions are extracted from the source inthe form of an ion beam of desired energy. Extraction is achieved byapplying a high voltage across suitably shaped extraction electrodes,which incorporate apertures for passage of the extracted beam. The ionbeam is then directed at the surface of the workpiece, such as asemiconductor wafer, in order to implant the workpiece with the dopantelement. The ions of the beam penetrate the surface of the workpiece toform a region of desired conductivity.

Several types of ion sources are commonly used in commercial ionimplantation systems, including the Freeman and Bernas types usingthermoelectrodes and powered by an electric arc, a microwave type usinga magnetron, indirectly heated cathode sources, and RF plasma sources,all of which typically operate in a vacuum. The ion source generatesions by introducing electrons into a vacuum chamber filled with thedopant gas (commonly referred to as the “feedstock gas”). Collisions ofthe electrons with dopant atoms and molecules in the gas results in thecreation of an ionized plasma consisting of positive and negative dopantions. An extraction electrode with a negative or positive bias willrespectively allow the positive or negative ions to pass through theaperture and out of the ion source as a collimated ion beam, which isaccelerated towards the workpiece. Feedstock gases include, but are notlimited to, BF₃, B₁₀H₁₄, B₁₂H₂₂, PH₃, AsH₃, PF₅, AsF₅, H₂Se, N₂, Ar,GeF₄, SiF₄, O₂, H₂, and GeH₄.

Presently, there are upwards of 10-15 implantation steps in thefabrication of state of the art devices. Increasing wafer sizes,decreasing critical dimensions, and growing circuit complexity areplacing greater demands on ion implant tools, with respect to betterprocess control, the deliverance of high beam currents at low energies,and a decrease in the mean time between failures (MTBF).

The parts of the ion implanter tool that require the most maintenanceinclude: the ion source, which must be serviced after approximately 100hours of operation, depending on its operating conditions; theextraction electrodes and the high voltage insulator, which usuallyrequire cleaning after a few hundred hours of operation; and thecryogenic pump

In the ideal case, all feedstock molecules would be ionized andextracted, but in reality a certain amount of feedstock decompositionoccurs, which results in the deposition on and contamination of thevacuum chamber and beamline. For example, boron residue readily depositson surfaces in the ion source region. The residue can form on lowvoltage insulators in the ion source, causing electrical short circuits,which can interrupt the arc required to produce thermionic electrons.This phenomenon is generally known as “source glitching,” and it is amajor contributor to ion beam instability, and may eventually causepremature failure of the source. The residue also forms on the highvoltage components of the ion implanter, such as the source insulator orthe surfaces of the extraction electrodes, causing energetic highvoltage sparking. Such sparks are another contributor to beaminstability, and the energy released by these sparks can damagesensitive electronic components, leading to increased equipment failuresand poor MTBF. While the ion source life expectancy for ion implantationsystems using non halide-containing source materials is generally around168 hours, with halide-containing materials such as GeF₄, the ion sourcelife can be as low as 10 hours due to the detrimental effects of residuedeposition on source operation.

Presently, vacuum chambers are cleaned using gases such as NF₃ and othernitrogen-containing gases as well as oxidizing species. For example,U.S. Pat. No. 6,135,128 in the name of Graf et al. relates to thecleaning of an ion source using NF₃ gas. However, NF₃ cleaning gasrequires an energetic source to release atomic fluorine, which uponrelease tends to be too aggressive, attacking every component in the ionsource region. In addition, the required energetic source, e.g., plasma,increases the cost of ownership (COO). U.S. Pat. No. 6,355,933 in thename of Tripsas et al. relates to the introduction of oxygenated gasesto the ion source for reacting with deposit forming species. Althoughoxidizing gases prove useful for the removal of carbonaceous species, itis disadvantageous if any component of the vacuum chamber or beamline isfabricated from carbon/graphitic material. Moreover, the introduction ofan oxidizing species to the vacuum chamber may promote the formation ofa surface oxide layer, or “rust,” on most metallic components, saidoxide layer potentially resulting in particle formation, entrapment ofgas molecules, shorts and premature filament failure.

Cryogenic vacuum pumps (cryopumps) are widely used in high vacuumapplications. Cryopumps are based on the principle of removing gasesfrom a vacuum chamber by cryocondensing and/or cryosorbing the gases oncold surfaces inside the cryopump. In cryocondensation, gas moleculesare condensed on previously condensed gas molecules, and thick layers ofcondensation can be formed, thereby, pumping large quantities of gas.Cryosorption is commonly used to pump gases that are difficult tocondense at the normal operating temperatures of the cryopump. In thiscase, a sorbent material, such as activated charcoal, is attached to thecoldest surface in the cryopump, typically a second stage of acryoarray. Because the binding energy between a gas particle and theadsorbing surface is greater than the binding energy between the gasparticles themselves, the gas particles that cannot be condensed areremoved from the vacuum system by adhering to the sorbent material.

Presently, ion implant cryopumps use inert gas, e.g., N₂, to purge awaythe cryogenically captured gas molecules and process residuesaccumulated during the process cycle. The inert gas purge assists inbringing the cryopump to ambient temperature, and adequately purges theevolving, previously cryosorbed gas molecules, including water vapor,hydrogen and organic compounds. The inert gas purge, however does notremove all the process effluents, hereinafter referred to as accumulatedprocess effluents, some of which underwent reaction to form non-volatilespecies during the warm-up of the cryopump and/or adhered to themetallic components of the pump. Presently, the only method of removingthe accumulated process effluents is through cryopump maintenance.

There are two types of cryopump maintenance evolutions, a vacuum siderebuild, and displacer side rebuild. Both forms of maintenance involveremoval of the cryopump from the implanter. The vacuum side rebuildrequires the pump be disassembled, cleaned, reassembled, andfunctionally tested and is recommended by the OEM on an annual basis.The displacer side maintenance involves disassembly, cleaning,reassembly, and functional testing of the displacer (gas flow cooling,actuating mechanism) of the cryopump and is recommended by the OEM on atri-annual basis.

In addition to the operational difficulties caused by residues in theion implanter and the cryopump, there are also significant personnelsafety issues due to the emission of toxic or corrosive vapors whencomponents are removed for cleaning. The safety issues arise whereverresidues are present, but are of particular concern in the ion sourceregion of the vacuum chamber because the ion source is the mostfrequently maintained component of the ion implanter. To minimize downtime, contaminated ion sources are often removed from the implanter attemperatures significantly above room temperature, which increases theemission of vapors and exacerbates the safety issue.

It would therefore be a significant advance in the art of ionimplantation to provide an in situ cleaning process for the effective,selective removal of unwanted residues deposited throughout theimplanter, particularly in the ion source region of the vacuum chamber,during implantation. Such in situ cleaning would enhance personnelsafety and contribute to stable, uninterrupted operation of theimplantation equipment.

An alternative to in situ cleaning is to provide a separate cleaningstation whereby contaminated components that have been removed from theimplanter can be cleaned safely without any mechanical abrasion whichmight damage delicate components such as graphite electrodes. It wouldtherefore also be a significant advance in the art of ion implantationto provide an off-line cleaning station that could be used toselectively and non-destructively clean components following removalfrom the implant system.

In addition, it would be a significant advance in the art to provide anin situ cleaning process for the removal of accumulated processeffluents from the cryopump thereby reducing or eliminating thefrequency of cryopump maintenance.

SUMMARY OF THE INVENTION

The present invention relates generally to a method and apparatus forcleaning internal components of an ion implantation tool. Specifically,the present invention relates to the in situ removal of residue from thevacuum chamber and components contained therein by contacting the vacuumchamber and/or components with a gas-phase reactive halide composition,e.g., XeF₂, for sufficient time and under sufficient conditions to atleast partially remove the residue from the components, and to do so insuch a manner that residue is removed selectively with respect to thematerials from which the components of the ion implanter areconstructed.

In one aspect, the invention relates to a method of cleaning a vacuumchamber of a semiconductor manufacturing tool, at least one component,or combination thereof, said method comprising:

-   -   (a) introducing an etchant gas from an etchant container into        the vacuum chamber;    -   (b) terminating introduction of the etchant gas into the vacuum        chamber upon attainment of a predetermined pressure in the        vacuum chamber; and    -   (c) reacting the etchant gas with a residue in the vacuum        chamber for a sufficient time to at least partially remove the        residue from the interior of the vacuum chamber, at least one        component contained therein, or combination thereof;        wherein the etchant gas is chosen to react selectively with the        residue in the vacuum chamber, the residue on the components        contained therein, or combination thereof, while being        essentially non-reactive with the interior of the vacuum        chamber, the components contained therein, or combination        thereof. Preferably, the etchant gas comprises a gas selected        from the group consisting of XeF₂, XeF₆, XeF₄, IF₅, IF₇, SF₆,        C₂F₆ and F₂.

In another aspect, the present invention relates to a method of cleaninga vacuum chamber of a semiconductor manufacturing tool, at least oneinternal component, or combination thereof, said method comprising:

-   -   (a) introducing an etchant material from an etchant container        into the vacuum chamber;    -   (b) terminating introduction of the etchant gas into the vacuum        chamber upon attainment of a predetermined pressure;    -   (c) dissociating the etchant material into a reactive halide        species in the vacuum chamber using a plasma source positioned        in said vacuum chamber; and    -   (d) reacting the reactive halide species with a residue in the        vacuum chamber for a sufficient time to at least partially        remove the residue from the vacuum chamber and/or the at least        one internal component.        Preferably, an inert gas from an inert gas source is introduced        into the vacuum chamber prior to dissociating the etchant        material.

In yet another aspect, the present invention relates to an apparatus forcleaning a vacuum chamber of a semiconductor manufacturing tool, atleast one internal component, or combination thereof, said apparatuscomprising:

-   -   (a) an etchant material source having an etchant material        disposed therein, wherein the etchant material source is        communicatively connected to, and is situated upstream of, the        vacuum chamber; and    -   (b) a valve between the etchant material source and the vacuum        chamber;    -   wherein said apparatus is further characterized by comprising at        least one of the following components (I) and (II):    -   (I) a heater for heating the etchant material source; and    -   (II) an inert gas source having an inert gas disposed therein,        wherein the inert gas source is communicatively connected to,        and is situated upstream of, the etchant material source.        Preferably, the etchant material comprises a gas selected from        the group consisting of XeF₂, XeF₆, XeF₄, IF₅, IF₇, SF₆, C₂F₆        and F₂.

In a further aspect, the present invention relates to a method ofcleaning a vacuum chamber of a semiconductor manufacturing tool, atleast one component, or combination thereof, said method comprising:

-   -   (a) introducing an etchant gas from an etchant container into        the vacuum chamber;    -   (b) withdrawing a plurality of gas species from the vacuum        chamber using a vacuum pump to effectuate a continuous flow of        the etchant gas therethrough; and    -   (c) flowing the etchant gas through the vacuum chamber for a        sufficient time to react the etchant gas with the residue to at        least partially remove the residue from the vacuum chamber, at        least one component contained therein, or combination thereof,    -   wherein the etchant gas comprises a gas selected from the group        consisting of XeF₂, XeF₆, XeF₄, IF₅, IF₇, SF₆, C₂F₆ and F₂.        Preferably, the etchant gas is chosen to react selectively with        the residue in the vacuum chamber, while being essentially        non-reactive with the interior of the vacuum chamber or the        components contained therein.

In yet another aspect, the invention relates to a method of cleaningaccumulated process effluent from the interior of a cryopump, saidmethod comprising purging the cryopump with at least two purge gases,said purge gases including nitrogen and at least one reactive gasselected from the group consisting of oxygen, ozone, nitrogen oxides,species that generate oxygen radicals in situ, and combinations thereof,wherein said method is characterized by at least one of the followingpurge process sequences (I), (II), and (III):

-   -   (I) (a) purging with essentially pure nitrogen for time x; and    -   (b) purging with the at least one reactive gas for time y,        wherein the at least one reactive gas is essentially pure;    -   (II) (a) purging with essentially pure nitrogen at time zero;    -   (b) blending the essentially pure nitrogen with the at least one        reactive gas, wherein the nitrogen and the at least one reactive        gas are no longer essentially pure;    -   (III) (a) purging with a mixture of nitrogen and at least one        reactive gas,        wherein the accumulated process effluent is substantially        removed from the interior of the cryopump.

A further aspect of the present invention relates to a method of ex situcleaning at least one component of a semiconductor manufacturing tool,said method comprising:

-   -   (a) positioning the component in an ex situ vacuum chamber;    -   (b) introducing an etchant gas from an etchant container into        the ex situ vacuum chamber;    -   (c) terminating introduction of the etchant gas into the vacuum        chamber upon attainment of a predetermined pressure in the        vacuum chamber; and    -   (d) reacting the etchant gas with a residue in the vacuum        chamber for a sufficient time to at least partially remove the        residue from the at least one component contained therein;    -   wherein the etchant gas is chosen to react selectively with the        residue on the at least one component, while being essentially        non-reactive with the interior of the vacuum chamber.

Yet another aspect of the invention relates to improved methods ofmanufacturing microelectronic devices such as semiconductors using theinventive methods and systems described herein.

Other aspects, features and embodiments of the invention will be morefully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an indirectly heated cathode ion source,illustrating three optional placements for the etchant material.

FIG. 2 is a schematic of the direct dissociative plasma configurationdescribed herein.

FIG. 3 is a schematic diagram of a 300 amu residual gas analyzer, usedto monitor by-products of the residue removal reactions.

FIG. 4 is an RGA trace as a function of time showing the efficacy ofXeF₂ in removing boron residue from an aluminum base layer.

FIG. 5 is an RGA trace as a function of time illustrating that XeF₂ doesnot react with a tungsten layer.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS THEREOF

The present invention relates to a method and apparatus for cleaning thevacuum chamber and/or beamline of an ion implantation system used in thefabrication of a microelectronic device. Specifically, the presentinvention relates to the in situ removal of residue from a vacuumchamber of the ion implanter and components contained therein bycontacting the vacuum chamber and/or components with a gas-phasereactive halide composition, e.g., XeF₂, NF₃, F₂, XeF₆, XeF₄, SF₆, C₂F₆,IF₅ or IF₇, for sufficient time and under sufficient conditions to atleast partially remove the residue from the components, and to do so insuch a manner that residue is removed selectively with respect to thematerials from which the components of the ion implanter areconstructed.

As used herein, “vacuum chamber” includes the source vacuum chamber, andthe ion source region including the source arc chamber, the sourceinsulators, the extraction electrodes, the suppression electrodes, thehigh voltage insulators, source bushing and the source turbomolecularpump.

As used herein, “beamline” includes the ion source region and othercomponents inside the vacuum system, including the beamline vacuumchamber, the accelerator column, interior ion optical components such aselectrostatic steerers and lenses, the beamline turbomolecular pumps andthe vacuum exhaust lines.

As used herein, “microelectronic device” corresponds to semiconductorsubstrates, flat panel displays, and microelectromechanical systems(MEMS), manufactured for use in microelectronic, integrated circuit, orcomputer chip applications. It is to be understood that the term“microelectronic device” is not meant to be limiting in any way andincludes any substrate that will eventually become a microelectronicdevice or microelectronic assembly.

As used herein, “residue” corresponds to the unused portion of theimplant gas (e.g., some portion of BF₃, PH₃, AsH₃, GeF₄, etc.), carriergas residue (e.g., fluorine, chlorine, oxygen, nitrogen, argon, etc.),as well as chamber material that is sputtered/deposited (e.g., tungsten,molybdenum and/or aluminum-containing species). For example, the residuemay include metals such as B, As, P, Ge, W, Mo and/or Al, compoundsbetween the B, As, P and/or Ge species and the W, Mo and/or Al species,as well as permutations of the materials of construction. The residuemay be conducting or non-conducting. Preferably, the residue is devoidof non-dopant components of the implant gas.

The reactive halide gas may for example include a XeF₂ vapor. XeF₂ willsublime at room temperature, but may be heated using a heater toincrease the rate of sublimation. XeF₂ is known to be an effectivesilicon etchant and has been used as a silicon selective etchant inMicro Electro Mechanical System (MEMS) device processing because it isextremely selective to SiO₂ and other dielectric materials.Specifically, XeF₂ reacts with silicon according to the followingreaction.

2 XeF₂ (g)+Si (s)→2 Xe (g)+SiF₄ (g)  (1)

Importantly, the silicon/XeF₂ reaction can occur without activation,i.e., plasma or thermal heating.

In this application, the use of XeF₂ as an etchant for metallic boron isdisclosed. Although not wishing to be bound by theory, it is thoughtthat the boron is etched according to the following reaction.

3 XeF₂ (g)+2 B (s)→3 Xe (g)+2 BF₃ (g)  (2)

The use of XeF₂ as an etchant for arsenic, phosphorus and germanium hasnot been reported to the best of our knowledge; however, XeF₂ may proveto be an effective etchant for these materials as well according to thefollowing reactions (3)-(5).

5 XeF₂ (g)+2 As (s)→5 Xe (g)+2 AsF₅ (g)  (3)

5 XeF₂ (g)+2 P (s)→5 Xe (g)+2 PF₅ (g)  (4)

2 XeF₂ (g)+Ge (s)→2 Xe (g)+GeF₄ (g)  (5)

Similar to the silicon/XeF₂ reaction, the reactions disclosed herein mayoccur with or without energetic activation.

Importantly, the method and apparatus taught herein is used to at leastpartially remove the residue from the components of the ion implanter,and to do so in such a manner that residue is removed selectively withrespect to the materials from which the components of the ion implanterare constructed, e.g., aluminum, tungsten, molybdenum, etc.. As usedherein, the term “at least partially remove” is defined as the removalof at least about 25 wt. %, more preferably at least about 50 wt. %,more preferably at least 75 wt. %, and most preferably at least about 90wt. % of the residue to be removed. The extent of residue removal and/orion implanter component removal may be determined using analyticaltechniques well known in the art including, but not limited to,temperature-programmed infrared spectroscopy (TPIR), Fourier TransformInfrared Spectroscopy (FTIR), electron paramagnetic spectroscopy (EPM),residual gas analysis (RGA), mass spectrometry, and combinationsthereof.

Several novel ways to deliver the gas-phase reactive halide composition,e.g., a composition including XeF₂, to the vacuum chamber and thebeamline for in situ cleaning therein are proposed, including a stagnantmode, a continuous mode, and a direct introduction mode. Althoughreference is made hereinafter to a XeF₂ composition, other reactivehalide compositions may be used including, but not limited to, XeF₆,XeF₄, SF₆, C₂F₆, IF₅ or IF₇. It is further noted that the XeF₂ oralternative reactive halide compositions may comprise, consistessentially of or consist of XeF₂ or alternative reactive halides.Preferably, the gas-phase reactive halide composition is devoid of orsubstantially free of an oxidizing species and a nitrogen-containingspecies, wherein the nitrogen-containing species comprises at least oneadditional element selected from the group consisting of O, F, and Br,unless indicated otherwise. Alternatively, the gas-phase reactive halidecomposition may include reducing species such as hydrogen and/or carbonmonoxide.

In addition, it is noted that the apparatuses described herein mayinclude improved low-pressure dopant gas supply arrangements whichpermit dopant gases to be delivered to the ion source unit at groundpotential, as described in U.S. Provisional Patent Application No.60/712,648 in the name of Robert Kaim et al. and entitled “Delivery ofLow Pressure Dopant Gas to a High Voltage Ion Source,” which is herebyincorporated by reference herein in the entirety.

In the stagnant mode, an etchant container with the XeF₂ compositiondisposed therein is communicatively attached to the chamber of the ionimplanter to be cleaned, wherein the etchant container and the chamberto be cleaned have a valve disposed therebetween. During cleaning, thevalve may be manually or remotely opened whereby the XeF₂ vapor ispermitted to fill the chamber to be cleaned until a pre-determinedpressure is attained. The etchant container may be moderately heated toincrease the sublimation rate and/or the sublimation pressure.

In a more preferred embodiment, the cleaning apparatus includes aseparate holding chamber of sufficient volume positioned between theetchant container and vacuum chamber. The XeF₂ may be flowed first intothe holding chamber and stored therein until a pre-determined pressurethreshold is reached. Such holding chamber serves to allow immediate gasflow to the vacuum chamber on demand and to shorten the “waiting-period”associated with sublimation. The walls of the holding chamber may beheated to permit higher pressure storage while avoiding condensation ofXeF₂ on interior surfaces of the chamber. The holding chamber mayfurther comprise flow-regulating devices, such as a mass flowcontroller, to achieve reproducible delivery of XeF₂ into the vacuumchamber.

Once the desired pressure in the vacuum chamber has been attained, thevacuum chamber is sealed and the XeF₂ permitted to react for sufficienttime and under sufficient conditions to at least partially remove theresidue from the vacuum chamber and the components contained therein.The vacuum chamber can then be evacuated and the cleaning processrepeated as needed. The evacuated gas mixture may be further directed toabatement units including, but not limited to, chemical and/or physicaladsorption beds, incinerators, wet scrubbers, or a combination thereof.

The internal pressure, time, and number of repeat cleanings may bereadily determined by those of ordinary skill in the art. The nature andextent of the cleaning of the residue may be empirically determinedwhile varying the time and/or contacting conditions (such astemperature, pressure, concentration and partial pressure) of the XeF₂composition to identify the process conditions producing a desiredresidue removal result. For example, the pressure of the XeF₂composition in the vacuum chamber may be about 0.3 Torr to about 4.0Torr, preferably about 0.3 Torr to about 0.7 Torr, and the length ofcleaning about 1 to about 4 minutes, which may be repeated about two (2)to about ten (10) times. Preferably, the pressure of the XeF2 is about0.35 Torr and the length of cleaning about 1 minute. Importantly, thepressure in the vacuum chamber during cleaning should be carefullymonitored as the pressure will gradually increase as the cleaningreaction proceeds and should plateau when the reaction has run itscourse.

A residual gas analyzer may be used to measure the concentration of XeF₂and other reaction byproducts, which may also be useful for monitoringthe progress of the cleaning process. A residual gas analyzer (RGA), asshown schematically in FIG. 3, may be attached to the vacuum chamber andused to monitor the by-products of the residue removal reactions. TheRGA may be a 200 amu or 300 amu analyzer, most preferably a 300 amuanalyzer.

Preferably, the XeF₂ gas is generated without energetic activation,although activation is contemplated herein. Thus, effective cleaning canbe performed at room temperature, although cleaning is contemplated attemperature in a range of about 0° C. to about 1000° C. depending on thecircumstances. Preferably, in the stagnant mode, the temperature is in arange from about 0° C. to about 50° C.

Importantly, the process parameters are chosen to ensure that thereactive halide gas is essentially non-reactive with the vacuum chamberand the beamline components material of construction. As used herein,“essentially non-reactive” corresponds to less than about 5% of thetotal reactive halide gas reacts with the components of the vacuumchamber and the beamline, preferably less than about 2%, most preferablyless than about 1%.

An example of the stagnant mode for cleaning an ion source region 10 isshown in FIG. 1, which includes a vacuum chamber 100, an arc chamber 16,the acceleration electrode 14, the deceleration electrode 12, thecathode 18, the anticathode 20 and the gate valve 110. The etchantcontainer 80 holding the XeF₂ may be communicatively connected to thearc chamber 16 by the dedicated vapor feed line 90 (as shown) oralternatively, although not shown in FIG. 1, the etchant container 80may be communicatively connected to the vacuum chamber 100 (i.e.,positioned outside of the vacuum chamber 100). To introduce the XeF₂ gasinto the arc chamber 16, valve 84 is manually or automatically opened topermit the XeF₂ to flow from the etchant container 80 to the arc chamber16. Alternatively, although not shown in FIG. 1, the XeF₂ from anetchant container such as 80, may be introduced into the arc chamber viaa reactive gas inlet line (e.g., component 22) instead of a dedicatedXeF₂ inlet line. Sublimation of the XeF₂ source may be assisted byheating the etchant container 80 using a heater including, but notlimited to, heater wires 88, conformal heating blankets, jackets orshrouds, electrical heating tape, heated fluids and/or gases, or anoven. In addition, temperature measurement device may be used including,but not limited to, a thermocouple 86. The entire etchant containerhousing 82 may be water cooled. Although not illustrated in FIG. 1, aholding chamber may be situated between the etchant container and thevacuum (i.e., if the etchant container 80 is positioned outside of thevacuum chamber 100) or arc chamber. Following at least partial removalof the residue from the interior of the chamber to be cleaned, valve 92is opened and the gases are evacuated using pump 96 via outlet line 94.In another embodiment of the stagnant mode, the residue is devoid oftungsten species.

In the continuous mode, an etchant container with the cleaning gascomposition disposed therein is directly or indirectly communicativelyattached to the vacuum chamber or to the arc chamber, and a vacuum pumpis withdrawing the cleaning gas and reaction products so that there is acontinuous flow of gases through the vacuum chamber or the arc chamber.An inert carrier gas may be arranged to flow continuously over the XeF₂composition in the etchant container to deliver a steady stream of XeF₂to the chamber to be cleaned. The flow rate of the carrier gas,temperature of the etchant container, and cleaning time are experimentalparameters readily determined by those skilled in the art. Similar tothe stagnant mode, a holding chamber may be situated between the etchantcontainer and the chamber to be cleaned.

An example of the continuous mode, wherein the etchant container iscommunicatively connected to the arc chamber, is shown in FIG. 1. Theetchant container 40 holding the XeF₂ composition is communicativelyconnected to the arc chamber 16 via the valve 42. Alternatively, XeF₂vapor may be introduced together with other reactive gases, dopant gasesor inert gases via the general purpose gas inlet line 22. Outlet valve92, pump 96 and outlet line 94 are positioned to withdraw gases from thevacuum chamber 100, thereby effectuating the continuous flow mode. Wheninert gas container 44, valve 46, valve 42 and valve 92 are open, andpump 96 is operating, inert gas flows continuously over the XeF₂composition in the etchant container 40 and the mixture is introducedinto the arc chamber 16. The gases egress out of the chamber via outletline 94. Inert gases contemplated herein include, but are not limitedto, argon, nitrogen, xenon, and helium. A further alternative includessublimation assistance by heating the etchant container 40 using aheater, as described previously with regards to the stagnant mode. Inremoval use thereof, cleaning may be effectuated by flowing the XeF₂mixture (or the pure XeF₂) continuously through the arc chamber whilethe ion source is on (i.e., a plasma is generated in the arc chamber) oroff. An alternative plasma-generating source for placement in the arcchamber or directly upstream of the arc chamber is also contemplatedherein. Preferably, the ion source is on during the continuous modecleaning process.

In addition, FIG. 1 illustrates the introduction of the XeF₂ compositioninto the vacuum chamber 100. In this embodiment, XeF₂ from etchantcontainer 60 is communicatively connected to the vacuum chamber 100 viaa dedicated inlet line. When inert gas container 64, valve 66, valve 62and valve 92 are open, and pump 96 is operating, inert gas flowscontinuously over the XeF₂ composition in the etchant container 60 andthe mixture is introduced into the vacuum chamber 100 via the dedicatedinlet line.

In yet another embodiment of the continuous mode, the etchant gas andthe dopant gas are introduced simultaneously to the arc chamberpermitting a continuous ion-implantation and cleaning process. Theamount of cleaning gas and the process conditions must be tailored toinsure the desired dopant species are not compromised, as readilydetermined by one skilled in the art.

In a still further embodiment of the continuous mode, cleaning may beeffectuated by alternating the continuous flow of the dopant gas (i.e.,BF₃ or other dopant gases during ion implantation) and the continuousflow of the cleaning gas to the vacuum chamber or the arc chamber, withor without an intermediate evacuation step. The dopant gas and thecleaning gas may be alternating between one and five times, as readilydetermined by one skilled in the art. This alternating dopantgas/cleaning gas methodology is advantageous relative to the currentindustry practice of alternating dopant species, because the cleaningschedule may be decoupled from and interleaved with the processingschedule, and more frequent cleaning may occur.

In the direct introduction mode, an etchant container with pre-measuredamounts of XeF₂ composition, e.g., in the form of pellets, is introducedinto the sealed vacuum chamber 100. The XeF₂ completely sublimates inthe vacuum chamber and the XeF₂ is permitted to react for sufficienttime and under sufficient conditions to at least partially remove theresidue from the ion source region components. The amount of etchant andthe time required for cleaning are readily determined by those skilledin the art. Methods for mechanical dispensing, i.e., etchant containers,are readily engineered by those skilled in the art. Following at leastpartial removal of the residue from the interior of the chamber to becleaned, valve 92 is opened and the gases are evacuated using pump 96via outlet line 94. Direct introduction cleaning may be repeated asnecessary.

In another embodiment of the invention, the reactive halide gas may forexample comprise a nitrogen trifluoride (NF₃) vapor. NF₃ is used in thesemiconductor industry as a fluorine source for plasma etching, e.g., insitu chamber cleaning of CVD reactors. Additional applications includeetching of polysilicon, silicon nitride, tungsten silicide and tungstenfilms. Specifically, NF₃ dissociates into reactive halide species in theplasma, such as fluorine radicals and/or fluoride ions, said reactivehalide species subsequently reacting with the residue to be removed. Forexample, if the residue includes boron, cleaning occurs according to thefollowing reaction.

3 F₂ (g)+2 B (s)→2 BF₃ (g)  (5)

Several novel ways to deliver the NF₃ compound to the ion source regionfor in situ cleaning therein are proposed, including a directdissociative plasma configuration.

In the direct dissociative plasma configuration, a NF₃ source 222 iscommunicatively connected to the arc chamber 210, with a valve situatedtherebetween 220 (see FIG. 2). As seen in FIG. 2, the NF₃ source iscommunicatively connected with the reactive gas, e.g., BF₃, inlet tube218, allowing introduction of NF₃ simultaneously with other ion sourcedopant materials. However, other means of introducing NF₃ into the arcchamber are contemplated, for example via a dedicated NF₃ inlet line.During cleaning, NF₃ enters the arc chamber 210 and the fluoride ionsare generated using the existing plasma equipment (e.g., the filament212, cathode 214 and the anticathode 216) or some additional electronicsarranged within the arc chamber 210. Inert, diluent gases are preferablyadded to the arc chamber to dilute the highly reactive fluoride ions.Parameters such as NF₃ flow rate into the arc chamber, amount of diluentgas, chamber pressure and time required for cleaning are readilydetermined by those skilled in the art. Multiple pressures and flowrates are also contemplated, wherein the different pressures and flowrates are used sequentially to effect different plasma shapes andconsequently different concentration profiles. Different profiles may beuseful for cleaning different areas of the arc chamber, i.e., outercomers, etc. Following at least partial removal of the residue from theinterior of the chamber, the gases are evacuated via an outlet line andoptionally abated.

Additional cleaning gases contemplated for introduction using the directdissociative plasma introduction mode, in addition to NF₃, include XeF₂,XeF₆, XeF₄, IF₅, IF₇, SF₆ and C₂F₆.

In another embodiment of the invention, the reactive halide gas isfluorine, for example as delivered from Advanced Technology MaterialsVAC cylinder (Danbury, Conn., USA). Fluorine is an extremely corrosivegas and can be used with or without thermal or electrical activation.Without activation, the fluorine gas can be admitted directly to thevacuum chamber, wherein the gas is permitted to spontaneously react forsufficient time and under sufficient conditions to at least partiallyremove the residue. If additional activation is required, components maybe heated or left at an elevated temperature and the gas permitted toreact for sufficient time to at least partially remove the residue. Inthe alternative, a plasma may be generated within the arc chamber (asdescribed previously) to further induce fluorine activation.

The embodiments described herein may be added directly to newlymanufactured ion implantation tools or in the alternative, implantersalready in use may be easily retrofitted with the cleaning systemsdescribed herein.

In a further embodiment, the etchant gas may be blended with theimplanting species, e.g., boron trifluoride, so that etching andimplanting may occur simultaneously, which is cost effective in terms ofminimization of down time and elimination of additional expensivedelivery systems. Thus, another embodiment of the invention relates to amethod of implanting an implant species while simultaneously etching orcleaning the vacuum chamber and/or beamline, preferably using a blend ofimplanting species and an etchant gas.

The advantages of the present invention include, but are not limited to,selective cleaning of unwanted residue in the vacuum chamber andbeamline of an ion implantation system, the ability to clean the residuewithout using plasma-induced radicals thereby minimizing damage to thecomponents of the vacuum chamber and beamline, and effective cleaning atroom temperature. Residue removal from the vacuum chamber and beamlineusing the methods introduced herein reduces source glitching andextraction arcing, thereby contributing to more stable operation of theion implanter. Further, the ion source lifetime and MTBF are increased,with a concomitant decrease in preventative maintenance costs and time.

In situ cleaning of the vacuum chamber and beamline should be performedabout 1 to 2 times per week, although the number of cleanings may bemore or less often depending on how often the ion implanter is used.Typically, the length of the entire cleaning operation is about 1 hour,although the cleaning time may be more or less.

To perform any of the cleaning operations described herein, the ionsource is left on or turned off (as indicated in the foregoingprocesses) and the source isolation valve is closed (for stagnant orcontinuous processes) or open (for continuous processes) prior tointroduction of the etchant gas (or the etchant container in the directintroduction mode). Following residue removal, normal ion implanteroperations may be resumed.

In yet another embodiment of the invention, off-line (ex situ) cleaningof the components of the ion source region using a vapor phase isdisclosed. In this embodiment, components from any part of the ionimplanter which are delicate (e.g., graphite-containing components) maybe cleaned off-line thereby eliminating exposure to conventionaloff-line cleaners, such as harsh abrasives or liquids. Off-line cleaningusing a vapor phase material is an advance in the art because abrasivescan damage the delicate components and liquids which enter the pores ofthe delicate components during cleaning must be pumped out of the poresduring pump down of the vacuum chamber.

In this embodiment, the ion source or any other power supplies areturned off, relevant isolation valves are closed, and the ion source orother vacuum chamber is vented to atmospheric pressure. Preferably, theion source region is allowed to cool to room temperature beforedisengagement of the components to be cleaned from the ion sourceregion. The components are removed from the implanter and positioned ina separate, off-line vacuum chamber with a simple pumping system andvalves. Alternatively, the components may be positioned in some otherhigh pressure vessel such as a supercritical fluid vessel altered forsaid ex situ cleaning. Etchant gas, for example XeF₂, is introduced intothe off-line vacuum chamber according to the teachings herein, forsufficient time and under sufficient conditions to at least partiallyremove the residue from the components. Following each cleaning phase,the toxic by-products are pumped away, optionally to abatement units, aspreviously described, to properly dispose of the toxic vapors.Preferably, the off-line vacuum chamber is a stand alone unit that isable to service numerous ion implanters, e.g., upwards of 10-12, in thefab.

In yet another embodiment, the present invention relates to the in situcleaning of the cryogenic pump.

As used herein, “accumulated process effluents” correspond to thosespecies that are not removable during the conventional cryopump purgeprocess using nitrogen as the purge gas. For example, the accumulatedprocess effluents may be species that underwent a chemical change whilethe cryopump was warmed to ambient temperature. Alternatively, theaccumulated process effluents may correspond to species that haveadhered to the metallic parts of the cryopump.

Nitrogen is the conventional gas of choice during the cryopump purgingprocess whereby the temperature of the cryopump is raised from 10-14K toambient temperature and the previously cryosorbed species are carriedaway within the purge gas to the exhaust system. In the presentinvention, a portion of the nitrogen purge gas may be replaced by areactive gas to remove or inhibit accumulated process effluent buildupin the cryopump. Reactive gases contemplated herein include, but are notlimited to, oxygen, ozone, nitrogen oxides, other species that generateoxygen radicals, and combinations thereof.

The purge gas(es) may be delivered to the cryopump using a processselected from the group consisting of: (i) 100% (“essentially pure”)nitrogen for x minutes followed by 100% (“essentially pure”) reactivegas for y minutes repeated n times, wherein n may be any integer between1 and 10 and [n×(x+y)] equals the cumulative length of this purgingprocess; (ii) 100% (“essentially pure”) nitrogen at time zero and 100%(“essentially pure”) reactive gas at the end of this cryopump purgingprocess, whereby the percentage of nitrogen decreases and the percentageof reactive gas increases continuously or in steps (equal or non-equalin dimension) temporally from time zero to the end of this cycle purge;(iii) 100% (“essentially pure”) nitrogen at time zero and less than 100%reactive gas at the end of this cryopump purging process, whereby thepercentage of nitrogen decreases and the percentage of reactive gasincreases continuously or in steps (equal or non-equal in dimension)temporally from time zero to the end of this cycle purge; (iv) (100−z) %nitrogen and z% reactive gas continuously throughout the purgingprocess; and (v) variations and combinations thereof. Preferably, “x” isin a range from about 10 minutes to about 120 minutes, preferably about10 minutes to about 20 minutes, “y” is in a range from about 10 minutesto about 120 minutes, preferably about 10 minutes to about 20 minutes,and “z” is in a range from about 0.01% to about 99.99%.

As defined herein, “essentially pure” corresponds a gas containing lessthan 5 vol. % contaminating species, preferably less than 2 vol. %, morepreferably less than 1 vol. %, and most preferably less than 0.5 vol. %.It is to be understood by one skilled in the art that a contaminatingspecies may include reactive as well as non-reactive gas species.

The foregoing purge gas(es) delivery options ((i)-(v)) may be appliedduring warm-up of the cryopump to ambient temperature, followingachievement of ambient temperature (i.e., the cryopump temperature wasincreased using 100% (“essentially pure”) nitrogen followed by theapplication of one or more of the foregoing purge gas delivery options)or a combination of both. Accordingly, for purposes of the presentinvention, time zero corresponds to the moment the pump is no longercryogenically cooled, or the moment when the pump achieves ambienttemperature, or some other moment when the accumulated process effluentcan be most efficiently removed, as readily determined by one skilled inthe art for the desired in situ cleaning.

Importantly, substitution of a reactive purge gas for at least a portionof the nitrogen purge gas will reduce buildup of the accumulated processeffluent in the cryopump, which has the advantage of reducing oreliminating the frequency of cryopump maintenance and concomitantlydecreases the tool downtime and the cost of ownership. In addition, theacidity level in the cold head of the cryopump may be decreased as aresult of the use of the reactive gas(es).

The features and advantages of the invention are more fully shown by theillustrative examples discussed below.

EXAMPLE 1

Test samples were prepared using electron beam deposition of aluminum,boron, tungsten and silicon on glass microscope slides. The aluminum wasused as a bottom layer barrier on the glass slide. Some samples werecapped with a protective silicon layer while others were left uncappedand allowed to oxidize. The test samples were sequentially placed intoan ex situ XeF₂ reactor and etched for 16 one-minute pulse-etch cyclesat a pressure of 300-400 mTorr at room temperature.

FIG. 4 illustrates the removal, as determined by RGA, of boron from aglass slide having a base layer of 500 nm of aluminum with 500 nm ofboron deposited thereon. There was no silicon capping layer thereforethe boron could have potentially formed an oxide layer prior to etching.The XeF₂ etch process removed most of the boron in about 4 cycles with aconcomitant increase in unreacted XeF₂, indicating that boron removalwas decreasing or had ceased altogether. Importantly, FIG. 4 illustratesthat the boron layer was readily removed using the XeF₂ system andmethod taught herein, even if an oxide layer had formed thereon prior toetching.

FIG. 5 illustrates the removal, as determined by RGA, of tungsten from aglass slide having a base layer of 500 nm of aluminum with 150 nm oftungsten deposited thereon. There was no silicon capping layer thereforethe tungsten could have potentially formed an oxide layer prior toetching. No tungsten compounds were observed by RGA however, thepresence of XeF₂ was significant, indicating that no tungsten removalwas occurring. Importantly, FIGS. 4 and 5 illustrate that the system andmethod taught herein selectively removes ion implantation residue, e.g.,boron, while being essentially non-reactive with the materials ofconstruction of the ion implanter, e.g., tungsten and aluminum.

While the invention has been described herein with reference to variousspecific embodiments, it will be appreciated that the invention is notthus limited, and extends to and encompasses various other modificationsand embodiments, as will be appreciated by those ordinarily skilled inthe art. Accordingly, the invention is intended to be broadly construedand interpreted, in accordance with the ensuing claims.

1. A method of cleaning a vacuum chamber of a semiconductormanufacturing tool, at least one component, or combination thereof, saidmethod comprising: (a) introducing an etchant gas from an etchantcontainer into the vacuum chamber; (b) terminating introduction of theetchant gas into the vacuum chamber upon attainment of a predeterminedpressure in the vacuum chamber; and (c) reacting the etchant gas with aresidue in the vacuum chamber for a sufficient time to at leastpartially remove the residue from the interior of the vacuum chamber, atleast one component contained therein, or combination thereof; whereinthe etchant gas is chosen to react selectively with the residue in thevacuum chamber, the residue on the components contained therein, orcombination thereof, while being essentially non-reactive with theinterior of the vacuum chamber, the components contained therein, orcombination thereof.
 2. The method of claim 1, wherein the semiconductormanufacturing tool is an ion implanter.
 3. The method of claim 2,wherein the at least one component is an ion source region component ofthe ion implanter.
 4. The method of claim 2, wherein the at least onecomponent is a beamline component of the ion implanter.
 5. The method ofclaim 2, wherein the at least one component is a turbomolecular pumpsituated in communication with the vacuum chamber, and used for pumpingthe vacuum chamber.
 6. The method of claim 1, wherein the etchant gascomprises a gas selected from the group consisting of XeF₂, XeF₆, XeF₄,IF₅, IF₇, SF₆, C₂F₆ and F₂.
 7. The method of claim 1, wherein theetchant gas comprises XeF₂.
 8. The method of claim 1, wherein theresidue comprises an element selected from the group consisting ofboron, phosphorus, germanium, molybdenum, tungsten, aluminum, andarsenic.
 9. The method of claim 1, wherein the predetermined pressure issubatmospheric.
 10. The method of claim 7, wherein the predeterminedpressure is from about 0.3 Torr to about 4.0 Torr.
 11. The method ofclaim 3, wherein an ion source in the ion source region comprises asource selected from the group consisting of an indirectly heatedcathode source, a Freeman source and a Bernas source.
 12. The method ofclaim 1, wherein said time is from about 0.5 minute to about 5 minutes.13. The method of claim 1, further comprising (d) evacuating the vacuumchamber following completion of said reacting.
 14. The method of claim13, further comprising repeating (a) through (d) at least once.
 15. Themethod of claim 1, wherein the etchant container contains an etchantmaterial, and wherein the etchant container is heated by a heater toincrease the rate of physical conversion of the etchant material intothe etchant gas.
 16. The method of claim 15, wherein the heater isselected from the group consisting of an oven, a conformal heatingblanket, electrical heating tape, heated fluids and/or gases, and heaterwires.
 17. The method of claim 1, wherein an inert gas is introducedinto the etchant container to transport the etchant gas to the vacuumchamber.
 18. The method of claim 17, wherein the inert gas comprises agas selected from the group consisting of argon, nitrogen, xenon andhelium.
 19. The method of claim 1, wherein the etchant container ispositioned in the vacuum chamber or positioned upstream of the vacuumchamber.
 20. The method of claim 19, wherein the etchant containercontains a pre-measured amount of an etchant material for generation ofthe etchant gas in the vacuum chamber.
 21. The method of claim 20,wherein the etchant material is a solid or a liquid.
 22. The method ofclaim 20, wherein the etchant material is pelletized XeF₂.
 23. Themethod of claim 1, wherein the reaction of the etchant gas with theresidue is effectuated without energetic activation.
 24. The method ofclaim 8, wherein a concentration of the elements in the residue isdetermined by an analytical technique selected from the group consistingof temperature-programmed infrared spectroscopy (TPIR), FourierTransform Infrared Spectroscopy (FTIR), electron paramagneticspectroscopy (EPM), residual gas analysis (RGA), mass spectrometry, andcombinations thereof.
 25. The method of claim 1, wherein the etchant gasis devoid of an oxidizing species and a nitrogen-containing species,wherein the nitrogen-containing species comprises at least oneadditional element selected from the group consisting of O, F, and Br.26. A method of cleaning a vacuum chamber of a semiconductormanufacturing tool, at least one internal component, or combinationthereof, said method comprising: (a) introducing an etchant materialfrom an etchant container into the vacuum chamber; (b) terminatingintroduction of the etchant gas into the vacuum chamber upon attainmentof a predetermined pressure; (c) dissociating the etchant material intoa reactive halide species in the vacuum chamber using a plasma sourcepositioned in said vacuum chamber; and (d) reacting the reactive halidespecies with a residue in the vacuum chamber for a sufficient time to atleast partially remove the residue from the vacuum chamber, the at leastone internal component, or combination thereof.
 27. The method of claim26, wherein the etchant material comprises a material selected from thegroup consisting of XeF₂, XeF₆, XeF₄, NF₃, IF₅, IF₇, SF₆, C₂F₆ and F₂.28. The method of claim 26, further comprising introducing an inert gasfrom an inert gas source into the vacuum chamber prior to dissociatingthe etchant material.
 29. An apparatus for cleaning a vacuum chamber ofa semiconductor manufacturing tool, at least one internal component, orcombination thereof, said apparatus comprising: (a) an etchant materialsource having an etchant material disposed therein, wherein the etchantmaterial source is communicatively connected to, and is situatedupstream of, the vacuum chamber; and (b) a valve between the etchantmaterial source and the vacuum chamber; wherein said apparatus isfurther characterized by comprising at least one of the followingcomponents (I) and (II): (I) a heater for heating the etchant materialsource; and (II) an inert gas source having an inert gas disposedtherein, wherein the inert gas source is communicatively connected to,and is situated upstream of, the etchant material source.
 30. Theapparatus of claim 29, wherein the etchant material comprises a compoundselected from the group consisting of XeF₂, XeF₆, XeF₄, IF₅, IF₇, SF₆,C₂F₆ and F₂.
 31. The apparatus of claim 29, wherein the at least onecomponent is an ion source of an ion implanter, said ion source selectedfrom the group consisting of an indirectly heated cathode source, aFreeman source and a Bernas source.
 32. The apparatus of claim 29,wherein the heater is selected from the group consisting of an oven, aconformal heating blanket, electrical heating tape, heated fluids and/orgases, and heater wires.
 33. The apparatus of claim 29, wherein theinert gas comprises nitrogen, argon, xenon, or helium.
 34. The apparatusof claim 29, wherein the at least one component is a beamline componentof an ion implanter.
 35. The apparatus of claim 29, wherein the at leastone component is a turbomolecular pump situated in communication withthe vacuum chamber, and used for pumping the vacuum chamber.
 36. Theapparatus of claim 29, wherein the etchant material is devoid of anoxidizing species and a nitrogen-containing species, wherein thenitrogen-containing species comprises at least one additional elementselected from the group consisting of O, F, and Br.
 37. A method of exsitu cleaning at least one component of a semiconductor manufacturingtool, said method comprising: (a) positioning the component in an exsitu vacuum chamber; (b) introducing an etchant gas from an etchantcontainer into the ex situ vacuum chamber; (c) terminating introductionof the etchant gas into the vacuum chamber upon attainment of apredetermined pressure in the vacuum chamber; and (d) reacting theetchant gas with a residue in the vacuum chamber for a sufficient timeto at least partially remove the residue from the at least one componentcontained therein; wherein the etchant gas is chosen to reactselectively with the residue on the at least one component, while beingessentially non-reactive with the interior of the vacuum chamber and thecomponent material itself.
 38. The method of claim 37, wherein thesemiconductor manufacturing tool is an ion implanter.
 39. The method ofclaim 37, wherein the at least one component comes from an ion sourceregion.
 40. The method of claim 38, wherein the at least one componentcomes from the beamline of the ion implanter.
 41. The method of claim37, wherein the etchant gas comprises a gas selected from the groupconsisting of XeF₂, XeF₆, XeF₄, NF₃, IF₅, IF₇, SF₆, C₂F₆ and F₂.
 42. Themethod of claim 37, wherein the etchant gas comprises XeF₂.
 43. Themethod of claim 37, wherein the residue comprises an element selectedfrom the group consisting of boron, phosphorus, germanium, molybdenum,tungsten, aluminum, and arsenic.
 44. The method of claim 37, wherein thepredetermined pressure is subatmospheric.
 45. The method of claim 44,wherein the predetermined pressure is from about 0.3 Torr to about 4.0Torr.
 46. The method of claim 37, wherein the at least one componentcomprises an ion source selected from the group consisting of anindirectly heated cathode source, a Freeman source and a Bernas source.47. The method of claim 37, wherein said time is from about 0.5 minuteto about 5 minutes.
 48. The method of claim 37, further comprising (e)evacuating the vacuum chamber following completion of said reacting. 49.The method of claim 48, further comprising repeating (b) through (e) atleast once.
 50. A method of cleaning a vacuum chamber of a semiconductormanufacturing tool, at least one component, or combination thereofof thevacuum chamber, said method comprising: (a) introducing an etchant gasfrom an etchant container into the vacuum chamber; (b) withdrawing aplurality of gas species from the vacuum chamber using a vacuum pump toeffectuate a continuous flow of the etchant gas therethrough; and (c)flowing the etchant gas through the vacuum chamber for a sufficient timeto react the etchant gas with the residue to at least partially removethe residue from the vacuum chamber and/or at least one componentcontained therein, wherein the etchant gas comprises a gas selected fromthe group consisting of XeF₂, XeF₆, XeF₄, IF₅, IF₇, SF₆, C₂F₆ and F₂,and wherein the etchant gas is chosen to react selectively with theresidue in the vacuum chamber, while being essentially non-reactive withthe interior of the vacuum chamber or the components contained therein.51. The method of claim 50, wherein the semiconductor manufacturing toolis an ion implanter.
 52. The method of claim 50, wherein the vacuumchamber comprises an ion source region.
 53. The method of claim 50,wherein the vacuum chamber comprises a beamline vacuum chamber.
 54. Themethod of claim 50, further comprising flowing a dopant gas from adopant source into the vacuum chamber to effectuate ion implantationtherein.
 55. The method of claim 54, further comprising repeating (a)through (d) at least once.
 56. The method of claim 50, furthercomprising dissociating the etchant gas into a reactive halide speciesin the vacuum chamber using an energetic source.
 57. The method of claim50, wherein the reactive halide species reacts with the residue to atleast partially remove the residue from the vacuum chamber.
 58. Themethod of claim 50, wherein the residue comprises an element selectedfrom the group consisting of boron, phosphorus, germanium, molybdenum,tungsten, aluminum, and arsenic.
 59. The method of claim 56, wherein theenergetic source comprises a plasma generator.
 60. The method of claim59, wherein the plasma generator comprises an ion source selected fromthe group consisting of an indirectly heated cathode source, a Freemansource and a Bernas source.
 61. The method of claim 56, wherein theenergetic source is positioned within or immediately upstream of saidvacuum chamber.
 62. The method of claim 50, wherein the reaction of theetchant gas with the residue is effectuated without energeticactivation.
 63. The method of claim 50, wherein the etchant gas furthercomprises an inert species selected from the group consisting of argon,nitrogen, xenon and helium.
 64. The method of claim 50, wherein theetchant gas comprises XeF₂.
 65. The method of claim 50, wherein aconcentration of the elements in the residue is determined by ananalytical technique selected from the group consisting oftemperature-programmed infrared spectroscopy (TPIR), Fourier TransformInfrared Spectroscopy (FTIR), electron paramagnetic spectroscopy (EPM),residual gas analysis (RGA), mass spectrometry, and combinationsthereof.
 66. The method of claim 50, wherein the etchant gas is devoidof an oxidizing species and a nitrogen-containing species, wherein thenitrogen-containing species comprises at least one additional elementselected from the group consisting of O, F, and Br.
 67. A method ofcleaning accumulated process effluent from the interior of a cryopump,said method comprising purging the cryopump with at least two purgegases, said purge gases including nitrogen and at least one reactive gasselected from the group consisting of oxygen, ozone, nitrogen oxides,species that generate oxygen radicals in situ, and combinations thereof,wherein said method is characterized by at least one of the followingpurge process sequences (I), (II), and (III): (I) (a) purging withessentially pure nitrogen for time x; and (b) purging with the at leastone reactive gas for time y, wherein the at least one reactive gas isessentially pure; (II) (a) purging with essentially pure nitrogen attime zero; (b) blending the essentially pure nitrogen with the at leastone reactive gas, wherein the nitrogen and the at least one reactive gasare no longer essentially pure; (III) (a) purging with a mixture ofnitrogen and at least one reactive gas, wherein the accumulated processeffluent is substantially removed from the interior of the cryopump. 68.The method of claim 67, wherein the reactive gas comprises oxygen. 69.The method of claim 67, wherein the cryopump is purged during cryopumpwarm-up.
 70. The method of claim 67, wherein the cryopump is purged atambient temperature.
 71. The method of claim 67, wherein the accumulatedprocess effluent comprises non-volatile species that were producedduring cryopump warm-up.
 72. The method of claim 67, comprising Sequence(I), further comprising repeating (a) and (b) at least once.
 73. Themethod of claim 67, comprising Sequence (II), wherein the blendingcomprises a process selected from the group consisting of continuous,equivalent steps, and non-equivalent steps.
 74. The method of claim 67,comprising Sequence (II), wherein the amount of nitrogen is less thanthe amount of at least one reactive gas.